Low profile compass with removable protective cover and magnetic bull&#39;s eye alignment system

ABSTRACT

A low profile compass of the type including a transparent base member and fluid-filled vial contains a directional indicator in the vial in the form of a circle which is alignable with another circle imprinted on the vial. A hinged cover assembly can be detented to selected positions and includes a mirrored sight line for direct line sighting, and a lower protective cover or shoe for the base of the compass also serves as a receptacle for instruction sheets and scales for use in taking directional readings as well as for orientation alignment on a topographic map and inclinometer readings.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of Ser. No. 09/123,071, filed Jul. 27,1998, now U.S. Pat. No. 6,357,128 for LOW PROFILE COMPASS WITH REMOVABLEPROTECTIVE COVER AND MAGNETIC BULL'S EYE ALIGNMENT SYSTEM, invented byMarlin D. Iden, incorporated by reference herein.

BACKGROUND AND FIELD OF INVENTION

This invention relates to compasses, and more particularly relates to anovel and improved compass which is extremely versatile, user-friendlyand accurate.

I have previously devised a recreational compass of the type having aninner vial including a compass needle and azimuth ring which isyieldingly mounted in a housing, reference being made to U.S. Pat. No.4,438,568 assigned to The Brunton Company of Riverton, Wyo., theassignee of this invention. This invention is directed to certainimprovements to produce more accurate results and readability of azimuthbearing, inclination angles and declination settings together with anovel and improved needle alignment system in a compact, compass designwhich can be positioned in a protective shoe and in such a way as toenable the use of a compass for most operations without removal from theshoe.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide for anovel and improved compass of the type designed for outdoor andrecreational purposes.

It is another object to provide for a novel and improved means forassembling a compass vial onto a base without positive attachment and insuch a way that the vial can be positively rotated to a desired positionbut is not subject to accidental movement or rotation.

It is still another object of the present invention to provide for ashoe which forms a protective cover and provides a tactile grip whenusing the compass for retention of the base of the compass as well asfor storage of various scales and instructional cards and wherein theshoe will enable efficient use of the compass without removal from theshoe.

Among other advantages and features of the present invention is a needlealignment system in which the compass is made up of a vial or capsulecontaining a magnet of molded plastic with magnetic particles embeddedtherein, a circle on the vial and a transparent disk mounted on themagnet which has a smaller diameter circle printed on it in the sameradial location as the printed circle on the vial. Accordingly,alignment is achieved in a bull's eye fashion with a concentric gapformed between the rings when in perfect alignment and which also servesas an optical level for the compass when viewed through a mirrored coverwhich is employed in cooperation with the compass vial assembly.

Another desirable feature is that the center compass vial assembly isallowed to move independently within the outer grip ring to setdeclination of magnetic North, an arrow being printed on the back sideof the center vial which is the North indicator and allows non-parallaxadjustment of less than 1°. This same adjustment feature can be employedto preset the vial assembly to take inclinometer readings off of thescale on the compass vial when the compass is placed on one of its sideedges in reading up or down inclinations. Still further, a penduluminclinometer is located within the vial having a clear film pendulumwith a printed center arrow of contrasting color as compared to thebackground of a card retained in the shoe to indicate tilt, or a givenvertical angle. Typically, this card may be graduated in 5° incrementsfor a total of 180° and is one of several cards stored in the reliefarea within the shoe.

As still another feature of the present invention, an azimuth ring isunited to the compass vial and aids in assembly of the compass vial tothe base and includes bearing as well as back bearing markings which canbe read through a magnifier on the base, the magnifier being designedwith an index line on its underside to eliminate parallax error andmagnify the azimuth scale for increased accuracy.

A novel and improved dual cover assembly includes a pair of covershinged about a common hinge pin(s) in such a way that the covers can bemoved to selected positions independently or together. When in theclosed position directly over the vial and base assembly, the innersight cover can be raised to expose the vial assembly, and the grip ringis readily accessible through opposite sides of the cover withoutremoving the cover away from the base. In addition, the cover includesan angle finder or protractor at its hinge area which is graduated inselected increments so that readings can be taken at an index point onthe hinge as an indication of the angle formed between the base andcover.

The foregoing is given more for the purpose of illustration and notlimitation with respect to different features of the compass.

The above and other objects, advantages and features of the presentinvention will become more readily appreciated and understood from aconsideration of the following detailed description of preferred andmodified forms of the present invention when taken together with theaccompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view of a preferred form ofcompass in accordance with the present invention;

FIG. 2 is a top plan view of the preferred form of invention shown inFIG. 1;

FIG. 3 is a side view partially in section of the preferred form ofcompass;

FIG. 4 is a top plan view enlarged of the base of the compass;

FIG. 5 is an enlarged cross-sectional view taken about lines 5—5 of FIG.4;

FIG. 6 is a plan view in detail of a portion of the cover;

FIG. 7 is a bottom plan view of the cover portion shown in FIG. 6;

FIG. 8 is an enlarged fragmentary view of the hinge portion of the covertaken about lines 8—8 of FIG. 6;

FIG. 9 is a cross-sectional view through the hinge end of the compassassembly;

FIG. 10 is a detailed view of one of the hinge axles shown in FIG. 9;

FIG. 11 is an end view of the hinge axle shown in FIG. 10;

FIG. 12 is a sectional view of the needle assembly;

FIG. 13 is an end view of the preferred form of compass assembly withthe mirrored portion of the sight cover in a raised position;

FIG. 14 is a bottom plan view of the base portion of the preferred formof compass assembly with the cover removed; and

FIG. 15 is a side fragmentary view, enlarged, of the cover portion in araised position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring in more detail to the drawings, a preferred form of lowprofile, compact compass assembly 10 is illustrated in FIGS. 1 to 15 andis broadly comprised of a transparent base member 12 having a housingwall 13 for compass vial 14 and surrounding azimuth ring 16, a firstcover member 18 and a second separable sight cover 20 provided with amirror 21 on its inner surface and there being a sight line 22 on themirror which is visible through an opening 23 in the first cover portion18. The base member 12 and first and second covers 18 and 20 areindependently hinged about a common hinge pin or axle 24, and the entireassembly is releasably insertable into a protective housing in the formof a soft pliable shoe 26.

As best seen from FIG. 1, the shoe 26 is not only adapted to receive thebase member 12 and cover portions 18 and 20 but is also designed toreceive a series of normally flat, white cards C which are affixedtogether at one end by a suitable grommet or eyelet G to provide acommon opening for insertion of lanyard L which also passes through analigned opening, not shown, in the shoe 26. The cards C not only serveas a contrasting background behind the transparent base member 12 butcan be used to display a selected scale or image behind the base member12. The shoe 26 is of generally rectangular configuration including aflat bottom portion 30 having upstanding side walls 32, a curved endwall 33 of generally semi-circular cross-sectional configuration toreceive the common hinged end of the base 12, covers 18 and 20, and anopposite end wall 34 provided with an upper curved lip 36 to surroundthe opposite end of the base member 12. The shoe is composed of a softrubber or rubber-like material dimensioned to fit snugly over the base12 and covers 18 and 20 and therefore has limited resiliency so that itcan be slipped on and off the base 12 of the compass. In addition, thebottom portion 30 effectively forms a receptacle or cavity beneath thebase member 12 for insertion of the cards C so that the cards C can beconveniently stored together and are readily interchangeable for usewith the compass in carrying out different functions as well as toprovide information.

As best seen in FIGS. 4, 5 and 12, the vial 14 is defined by atransparent sealed enclosure or capsule 38 of cylindrical configurationhaving a flat circular top wall 39 and enlarged circular bottom wall 40with upper and lower spaced shoulders 41 and 42 around the outerperipheral wall of the enclosure 38. The azimuth ring 16 is mounted onthe enlarged circular bottom wall 40 of the capsule, and the capsule isfilled with a clear damping liquid to dampen the movement of the needleassembly to be described.

A center pivot 46 is molded to the bottom wall 40, and a magnet 48 witha raised central jeweled bearing 50 rests on the upper pointed end ofthe pivot 46; also a cover 52 is ultrasonically welded to the magnet 48by means of energy directors 53. A feature of the vial is theutilization of a clear plastic disk 54 sandwiched between the magnet 48and cover 52 with a circle T surrounding the letter “N” to designateNorth being imprinted on the disk 54. A second circle X with a radiallyextending arrow A is imprinted on the bottom wall 40 of the vial 14.

In taking inclinometer readings, an arrow I is imprinted on a cleartriangular disk or pendulum 56 which is loosely suspended from the pivot46. Specifically, the arrow I is of contrasting color, compared to thewhite background of the cards C and can be used in cooperation with aninclinometer scale on one of the cards C to read and indicate aparticular tilt angle when the compass 10 is placed on its side andtilted. The cards C may contain various map scales, survival tips, sinetables, inclinometer scales, first aid tips as well as instructions onuse of this instrument.

The vial 14 is releasably inserted in the housing 13 on the base member12, and a support ring 60 which is affixed to the outer peripheral wallof the vial 14 is provided with spring-like, upwardly projectingcircumferentially spaced tabs 62 in radially outwardly spaced relationto correspondingly spaced flat surfaces 64. The vial 14 and support ring60 are dimensioned to be passed upwardly into the circular housing wall13 until the azimuth ring 16 is firmly seated within the recessedunderside 66 of the housing. In order to rotate the azimuth ring 16, agripping ring 68 is assembled onto the housing wall 13 and the vial 14,the ring 68 having circumferentially spaced, spring-like tabs 69 whichare inserted downwardly in close-fitting engagement between the tabs 62and flat surfaces 64 and with the outer peripheral wall 67 insurrounding relation to the housing wall 13. Specifically, the tabs 69are wedged between the flat surfaces 64 and tab 62 so that rotation ofthe grip ring 68 will cause the capsule to rotate independently of orwith respect to the housing 13. Once in position, the grip ring 68 canbe manually rotated to set declination of magnetic North. For thispurpose, as shown in FIG. 14, the back side of the azimuth ring 16 isgraduated in 2° increments for a total of 60° both East and West ofNorth. The arrow A on the center vial is the North indicator and enablesa non-parallax adjustment of less than 1°.

The azimuth ring 16 has a dial 70 which is graduated in 1° incrementsand read through a raised magnifying prism 65 on the base 12, the latterhaving an index line designated at L1 on its undersurface to eliminateparallax error. Preferably, the dial 70 has graduations numbered every10° with the bearing and back bearing graduations marked in differentcolors, the back bearing graduations B1 being in inner concentricrelation to the bearing graduations B2. Parallel lines L2 may extend atspaced intervals across the azimuth ring 16, as shown in FIG. 4, fororientation alignment in a North-South direction on a topographic map.

Preferably, the magnet 48 is composed of a molded plastic material withpermanent magnetic particles embedded therein, such as, neodymium ironboron. Alignment is achieved between the first circle T pointing toNorth and placing the second circle X in bull's eye fashion within thefirst circle T so that a concentric gap is formed between the circleswhen in perfect alignment. In other words, the circle X should appearinside of the circle T with a uniform space or gap being perceivablearound the entire outside periphery of the inner circle X, for example,as illustrated in FIG. 4.

The dual cover assembly as described is designed to perform differentfunctions in conjunction with taking various readings. To this end, thecover 18 is of shallow generally cup-shaped configuration and providedwith the offset opening 23 aligned over the vial 14 and side recesses 74through which diametrically opposed surfaces of the grip ring 68 projectto permit rotation of the capsule 14 and azimuth ring 16. A pair of ribs76 run lengthwise of the cover 18 and flank opposite sides of theopening 23, as shown in FIG. 2, the upstanding ribs 76 being of a widthto receive the sight cover 20 therebetween when the latter is moved intoa closed position overlying the opening 23. As shown in FIG. 7, thesight cover 20 is essentially flat but has a slight oval-shaped recess78 on its undersurface to receive a sighting mirror 79 having a firstportion E of the sight line 22 running lengthwise of the mirror. Alimited opening 80 is formed centrally of the hinged end of the sightcover 20 and a second portion F of the sight line 22 extends from theopening 80 toward the mirror 79 to assist in sighting on a target, forexample, as illustrated in FIGS. 13 and 15 which illustrate the sightcover 20 at an acute angle to the base member 12. As a result, the usercan sight through the opening 80 and manually rotate the gripping ring68 and vial 14 until the circle X moves into alignment with the circleT. This serves the added function of indicating whether the compass isbeing held level or in a horizontal position, for example, if the gapbetween circles X and T is not uniform at opposite ends extending on aradial line from the pivot.

The hinge portions 18′ and 20′, respectively, at one end of the covers18 and 20 are aligned with and interposed between the hinge portions 12′at one end of the base member 12, see FIGS. 9 and 14, and are securedtogether by a pair of hinge pins or axles 24 inserted through oppositesides of the aligned hinge portions. Each hinge pin 24 iscorrespondingly formed with an enlarged head 82, and longitudinallyextending lugs 84 spaced apart by a common groove 85 extending radiallythrough one-half of the thickness of the pin and communicating with anaxially extending recess 86, as shown in FIG. 10. The lugs 84 definedetents which engage scalloped portions 88 along the inner surface ofeach hinge portion 20′ of the sight cover 20 so as to yieldingly resistopening and closing movement of the sight cover 20 and permit it to beselectively advanced to the desired angle with respect to the vial 14for sighting purposes. Another lug 84′ adjacent to the head 82 of eachpin 24 is aligned with and fits snugly in a recessed portion 90 on oneof the hinge portions 12′ of the base member 12 so as to lock each pin24 against rotation.

The recess 86 formed in each of the hinge pins 24 enables the lugs 84 toyieldingly resist movement of the sight cover 20; and the scallopedportions 88 are so formed as to permit the sight cover to move atincrements of 45°, 90°, 120° and 180°, or a total of four stops, up to afull 180°. An angle finder or protractor P is imprinted on one side ofthe outermost hinge portion 18′ of the cover 18 to display anglemarkings which may be graduated 180° in 5° increments. An index mark M′on the head 82 of one of the hinge pins 24 inside of the protractor Premains stationary when the cover is rotated and therefore serves as areference line to read the angle formed between the base 12 and cover18. Typically, this would be done by first opening the sight cover 20and then rotating the cover 18 to a specific angle so that the detents84 on the hinge pins 82 will not interfere with limited rotation of thecover 18 to a specific angle or increment.

In use, the declination of magnetic North is adjusted according to thegeographical area in which the compass is to be used by rotating thegripping ring 68 to preset the arrow A with respect to the declinationscale D on the back of the base member 12, as shown in FIG. 14. Once thedeclination is set, a bearing is taken by holding the compass level andsighting through the sight 80 and along the sight lines E and F. Thegripping ring 68 is rotated with the vial 14 until the circle X isbrought into alignment with the circle T as described, and the bearingcan be read from the scale beneath the magnifier 65. The foregoing isaccomplished with the cover 20′ raised at an angle approximating thatshown in FIG. 15 and which would essentially be the first increment towhich the cover is pivoted about the hinge axle 24. It will be apparentthat the bearing may be taken by sighting as described and directlyviewing the circles X and T in the vial 14 without viewing through themirror.

The back bearing reading on the outer scale may be taken simultaneouslyso that when necessary to return to the point of origin, the line oftravel is established by rotating the ring 68 until the back bearingreading appears under the magnifier 65. With the compass held level, thecircle T is free to rotate and, by turning one's body until the circle Xis aligned with the circle T, the sight line 22 will then indicate theline of travel.

In order to read from a topographic map, the compass 10 is placed on themap so that the edge of the base 12 is aligned between the two points,the origin and destination. The azimuth ring 16 is then rotated alongwith the capsule 14 until the orienting parallel lines L2 on the azimuthring 16 are parallel to the North lines on the map and the circle Xpoints to magnetic North on the map. The bearing to the target will thenappear beneath the index line L1 of the magnifier 65.

Inclinometer readings may be taken without removing the protective cover18 by placing the compass on one side edge and opening the sight cover20. An inclinometer scale, not shown, corresponding to the declinationscale shown in FIG. 14 except that it is graduated in both directionsfrom 0° to 90° rather than to 60°, is imprinted on a separate card Cplaced beneath the base member so that a reading can be taken directlythrough the capsule 14. When the compass is placed on its side with themirror 79 extending at 45° outwardly to the left, the object to besighted is lined up with the sight line F thereby directly aligning thependulum arrow I with the scale on the card from which a reading may betaken directly.

The compass of the present invention enables inclinometer readings to betaken without the card C by first calibrating the capsule so that thegraduated dial 70 may be used to take readings. The compass is removedfrom the shoe 26 and the vial 14 is rotated by holding the azimuth ring16 stationary until the arrow A on the orienting circle X points to aninclination index mark M on the back of the base member 30, as shown inFIG. 14. The cover portion 18 is closed and the sight cover 20 is openedto 45°, and the shoe 26 is replaced over the base member 12. In readingthe inclination of an object which is above the horizon, the compass ispositioned on its side edge with the sight cover 20 extending outwardlyto the left, and the object is sighted through the sight hole 80; theline 19 on the cover 18 aligned with the sight cover line 22. Theazimuth ring 16 is then rotated until the arrow A is aligned with theinclination arrow T while maintaining the sight lines 19 and 22 inalignment. The inclination angle is then read on the graduated dial 70by taking the reading at the index line L1 through the index lens 65.

The same procedure is followed in reading an inclination below thehorizon except that the compass is placed on its side edge with thesight cover extending outwardly to the right. Also, the inclinationangle is read on the graduated dial 70 at the index line L1 through theindex lens 65.

A second magnifier 95 in the base member 12 is illustrated in FIGS. 4and 14, the magnifier 95 being located just radially outwardly of themagnifier 65 and somewhat larger than the magnifier 65 to assist inreading scales or fine print for map navigation.

While a preferred form of invention is herein set forth and described,it is to be understood that various modifications and changes may bemade therein including but not limited to the construction andarrangement of elements as well as their composition without departingfrom the spirit and scope of this invention as defined by the appendedclaims and reasonable equivalents thereof.

I claim:
 1. In a compass having a base member and a compass capsulefilled with fluid and containing a magnet having a directional indicatorthereon, said capsule facing upwardly from an upper surface of said basemember, the combination therewith comprising: a protective shoe composedof a soft pliable material including a bottom wall, opposite side andopposite end walls at least partially surrounding an outer periphery ofsaid base member while leaving said upper surface and said compasscapsule exposed.
 2. In a compass according to claim 1 wherein said shoeis composed of a resilient material and is dimensioned for snug-fittingbut releasable engagement with said base member.
 3. In a compassaccording to claim 1 wherein said base member is transparent and saidshoe includes a receptacle for printed materials beneath said basemember, said materials being of a contrasting color to any printing onsaid base member.
 4. In a compass according to claim 1 wherein saidopposite end walls are of generally concave-convex configuration anddimensioned to be in snug-fitting engagement with opposite ends of saidbase member.
 5. In a compass according to claim 1 wherein said basemember and said shoe are of generally rectangular configuration, a covermember and means pivotally connecting said cover member to said basemember.
 6. In a compass having a transparent base member and adirectional indicator mounted on an upper surface of said base member, aprotective shoe composed of a soft pliable material disposed insnug-fitting but releasable engagement with said base member whileleaving an upper surface and said directional indicator exposed, and anupper cover in hinged engagement with said base member for pivotalmovement with respect to said base member and said shoe.
 7. In a compassaccording to claim 6 wherein said base member is transparent, an uppercover in hinged engagement with said base member to undergo pivotalmovement with respect to said base member.
 8. In a compass having a basemember and a compass needle disposed in a vial mounted on said basemember, the combination therewith comprising: a cover member for saidbase member, common ends of said cover member and said base memberextending beyond said vial and including hinge portions; and at leastone hinge pin inserted through said hinge portions, said hinge pinincluding a detent engagable with scalloped recesses along an innersurface in at least selected of said hinge portions to yieldingly resistpivotal movement of said cover member with respect to said base member.9. In a compass according to claim 8 wherein said cover member includesa first cover portion dimensioned to substantially overlie said basemember and a second cover portion pivotal about said base memberindependently of said first cover portion.
 10. In a compass according toclaim 8 wherein said cover portion has a slight line on its undersurfacealigned in centered relation to an opening in said first cover portion.11. In a compass according to claim 10 wherein said opening in saidfirst cover portion is aligned over said compass needle and said sightline is aligned with an axis through said compass needle.
 12. In acompass according to claim 11 wherein said compass needle is disposedwithin a clear plastic vial mounted in an opening in said base member.13. In a compass according to claim 12 wherein said detent is defined bylugs aligned with said hinge portions in said second cover portion. 14.In a compass according to claim 8 wherein an index element is providedon one end of said hinge pin and graduated markings are provided on anexposed end of one of said hinge portions at said end of said hinge pinto provide an indication of the angle formed between said base memberand said first cover portion.
 15. In a compass having a base member anda compass capsule filled with fluid and containing a magnet having adirectional indicator thereon, the combination therewith comprising: aprotective shoe composed of a soft pliable material including side andend walls at least partially surrounding an outer periphery of said basemember while leaving said compass capsule exposed, said base memberbeing transparent and said shoe including a receptacle for printedmaterials beneath said base member.